[extension types] Extension type does not get a highlight in DartDoc

[navaronbracke]

Any symbol references for an extension type symbol do not get the right highlight color in DartDoc:

Tooltips in VSCode do work though, so it's just the highlight color.

Example:

import 'dart:js_interop';

@JS()
@anonymous
@staticInterop
extension type BasicParameters._(JSObject _) {
  /// Create a [BasicParameters] instance using the given [callback].
  external factory BasicParameters({JSFunction callback});
}

Here the [BasicParameters] reference is not in light green (as it is for classes).

- Dart 3.2.0-189.0.dev (dev) (Thu Sep 21 21:03:12 2023 -0700) on "macos_x64"
- on macos / Version 13.5.2 (Build 22G91)
- locale is en-BE

#### Process info

| Memory |  CPU | Elapsed time | Command line                                                                    |
| -----: | ---: | -----------: | ------------------------------------------------------------------------------- |
|  59 MB | 0.0% |     02:10:41 | dart devtools --machine --try-ports 10 --allow-embedding                        |
| 688 MB | 0.0% |     02:10:41 | dart language-server --protocol=lsp --client-id=VS-Code --client-version=3.72.2 |

[srawlins]

Forgive the seemingly nitpicky question, but the issue is with how doc comments are highlighted in the IDE, yes? This is different from Dartdoc, which is a tool that uses doc comments to generate HTML documentation.

[bwilkerson]

Interesting. Navigation also works, so we appear to be resolving the reference correctly.

My guess, without looking at the code, is that there's a test somewhere that checks what kind of element (declaration) the identifier resolved to and it doesn't correctly handle the element kind for extension types.

[navaronbracke]

Forgive the seemingly nitpicky question, but the issue is with how doc comments are highlighted in the IDE, yes? This is different from Dartdoc, which is a tool that uses doc comments to generate HTML documentation.

Yes, the issue is about doc comments. Forgive me if I had the notion of "Dartdoc" wrong (which I assumed is a doc comment with /// for Dart code)

[srawlins]

No worries; I have to make sure that dartdoc, the tool, is doing the right thing too, so just making sure 😁

[bwilkerson]

https://dart-review.git.corp.google.com/c/sdk/+/336601